This invention relates to the production of chloric acid, HClO.sub.3. Chloric acid can be used in the formation of chlorine dioxide, a commercial bleaching and sanitizing agent.
Chloric acid is a known compound which has been made in laboratory preparations by the reaction of barium chlorate with sulfuric acid to precipitate barium sulfate and produce a dilute aqueous solution of chloric acid which was concentrated by evaporation of water under partial vacuum. In another method, sodium chlorate is reacted with an acid such as hydrochloric acid or sulfuric acid to produce an aqueous solution of chloric acid containing sulfate or chloride ions as impurities. In addition, commercial processes for producing chlorine dioxide form chloric acid as an intermediate.
U.S. Pat. No. 3,810,969 issued May 14, 1974 to A. A. Schlumberger teaches a process for producing chloric acid of high purity by passing an aqueous solution containing from 0.2 gram mole to 11 gram moles per liter of an alkali metal chlorate such as sodium chlorate through a selected cationic exchange resin at a temperature from 5.degree. to 40.degree. C. The process produces an aqueous solution containing from 0.2 gram mole to about 4.0 gram moles of HClO.sub.3.
Chloric acid, however, up to the present time, has not been produced or available commercially because of the high manufacturing costs and/or the undesired impurities present in the solutions of HClO.sub.3 made by these reactions.